The location of a User Equipment (UE) needs to be obtained at the network side for the purposes of e.g. lawful interception, emergent call, location-based charging, cell-level positioning, etc. A core network may be provided with cell-level identifier information of the UE in current standardized procedures of Attach, Tracking Area Updating (TAU), Service Request, X2 (an interface) Handover (HO), S1 (an interface) HO, etc. A Location Reporting procedure is also defined in the standards to obtain precise information about the current cell of the UE, in which the identifier of a cell currently serving the UE may be inquired immediately or an evolved Node B (eNB) may be configured to notify a Mobility Management Entity (MME) of the identifier of a serving cell immediately upon the UE changes the serving cell. For example, the MME sends a location reporting condition to the eNB in a Location Reporting Control message. The eNB sends cell identifier information of the UE to the MME in a Location Report message when the location reporting condition is satisfied.
In a Long Term Evolution-Advanced (LTE-A) system, a Relay Node (simply an RN) is introduced to improve network coverage. The RN is connected wirelessly with a Donor Evolved Node B (DeNB). A cell with which the RN is connected is a donor cell, and a cell on which a UE camps or with which the UE is connected is a serving cell of the UE. For high mobility scenario, the RN can be deployed in e.g., a railway, for the purposes of reducing the handover rate of the UE, improving the signal quality in a carriage, etc. In the case of the UE moving from a place A to a place B, but the RN serving the UE unchanged, the serving cell of the UE keeps unchanged. If information about the serving cell of the UE is reported as in the prior art, then the network side may consider the UE almost stationary according to the unchanged information about the serving cell, although the UE has actually moved far away. Obviously positioning for the UE is inaccurate from the information about the serving cell alone in the prior art.